A retrograde cystogram is a radiographic study of the bladder, made after a direct injection of a radiopaque contrast material by means of a urethral catheter.
A retrograde cystogram is performed to evaluate the structure of the bladder and identify such bladder disorders as cystitis, polyps, stones, and tumors. It may also be used to diagnose recurrent urinary tract infections due to urine reflux (backward flow) into the ureters. This examination is commonly performed as an emergency procedure on patients with gross hematuria (blood in urine) due to a pelvic fracture or severe trauma to the abdomen, in order to detect rupture of the bladder. Retrograde cystography is frequently done on children being evaluated for a congenital abnormality, obstruction, or urethral stricture. When the urethra is also being evaluated, the study is called a cystourethrogram. If the bladder or urethra is evaluated while the patient is voiding (urinating), the study is called a voiding cystourethrogram or VCUG. A voiding cystourethrogram is often performed when the bladder is full to check for any reflux or other problems during urination.
The physician should be alerted to any previous history of an allergic reaction to an iodine-based contrast material. Since the contrast medium is injected directly into the bladder instead of the venous circulation, allergic reactions are extremely rare. A retrograde cystogram should not be performed, however, on patients who have had recent bladder surgery or an obstruction that interferes with the placement of a urinary catheter. Patients with an active urinary tract infection or who may be pregnant should not be given a retrograde cystogram.
To administer a retrograde cystogram, a doctor or nurse will insert a thin tube-like instrument called a Foley catheter through the patient's urethra and into the bladder. The contrast medium is then injected through the catheter into the bladder. The catheter can be inserted in an outpatient clinic before the patient is taken to the radiology department. It may also be inserted by an emergency physician when a retrograde cystogram is ordered on a severe trauma patient. The cystogram can be performed in the emergency department using a portable x-ray machine.
After the Foley catheter is inserted, 250-300 mL of a water-soluble contrast medium is injected into the bladder and the catheter is clamped. A diluted contrast agent (usually 30% sodium iodide) is used since the contrast medium is not injected intravenously. An AP (anteroposterior) view of the full bladder is taken with the tube angled 10-15 degrees caudal (in the direction of the patient's feet) to project the pubic symphysis away from the base of the bladder. The patient is turned 45 degrees onto each side for two oblique views of the bladder and completely sideways for a true lateral view. The films are reviewed by the radiologist. If no other films are needed the catheter will be removed and a post-void film is taken. If the patient is unable to urinate, the clamp will be removed, the contrast medium will then empty from the bladder through the tube, and a post-drainage film will be taken. During a voiding cystogram, films are taken by the radiologist under fluoroscopy while the patient is voiding in order to image any urethral abnormalities or urinary reflux.
A retrograde cystogram usually takes from 30 minutes to one hour, depending on how many films are requested by the radiologist.
This examination can also be performed with a radioactive tracer (isotope) in the nuclear medicine department. A cystogram performed with a tracer is known as a radionuclide retrograde cystogram.
A CT scan of the bladder may also be ordered after the injection of a radiopaque contrast material.
Laxatives or enemas are sometimes given before the procedure to eliminate gas and fecal material that may prevent proper visualization of the bladder. The patient will be given a hospital gown. The x-ray technologist will explain the procedure and take a detailed patient history concerning allergies, the possibility of pregnancy, and current medical problems. The patient is usually requested to sign a consent form.
The patient may have some burning on urination for a few hours after the test, due to the irritation of the urethra from the catheter. The discomfort can be reduced by a liberal fluid intake, which will dilute the urine.
A normal result reveals no anatomical or functional abnormalities of the bladder.
Abnormal results may indicate:
- calculi (stones)
- inflammation (cystitis)
- blood clots
- injury (bladder tear)
- cystocele (prolapse of the bladder into the vaginal cavity, common after childbith)
- ruptures (imaged as flame-like leakages of the contrast material superior or lateral to the bladder)
- tumors (visualized in the bladder or in an adjacent structure such as the vagina or prostate)
- reflux (urine passing backward from the bladder into the ureters, causing infection)
Health care team roles
The procedure is ordered by the physician. The patient may be catheterized by a physician or nurse. The x-ray technologist prepares the contrast medium for injection and takes all the overhead views of the bladder. If the portable x-ray machine is used to perform the cystogram, all staff members remaining in the room must be shielded. The x-ray technologist works closely with the doctors and nurses to make sure the patients are catheterized before arriving in the radiology department and that an enema or laxative has been administered.
The x-ray technologist must explain to the patient that it is necessary to fill the bladder completely to see a detailed image of the bladder outline. The patient may experience some discomfort with a full bladder; however, the films are taken at once and the catheter is removed or unclamped. If a film must be taken while the patient is voiding, the lights can be dimmed and the water tap turned on to help the patient relax. The radiology technologist must be certified and registered with the American Society of Radiologic Technologists.
Bladder— A balloon-like organ located in the lower pelvis that stores urine.
Catheter— A thin tube used to inject fluids into or withdraw fluids from the body.
Fluoroscope— An under-table x-ray tube used in conjunction with a television monitor that allows immediate visualization of the x-ray image.
Hematuria— The presence of blood in the urine.
Stones— Also known as calculi, stones result from an excessive build-up of mineral crystals in the kidney. Symptoms of stones include intense pain in the lower back or abdomen, urinary tract infection, fever, burning sensation on urination, and/or blood in the urine.
Ureter— The tube that carries urine from the kidney to the bladder.
Urethra— The tube that empties urine from the bladder to the outside of the body.
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American Kidney Fund. 6110 Executive Blvd., #1010, Rockville, MD 20852. 800-638-8299.
National Kidney Foundation. 30 East 33rd St., New York, NY 10016. (800) 622-9010 or (212) 889-2210.
National Kidney and Urologic Diseases Information Clearinghouse. 3 Information Way, Bethesda, MD 20892-3580. (301) 654-4415.